Semiconductor device fabrication usually involves many processes, including a rough polishing and/or a finish polishing for generating a smooth surface on a wafer. The finish polishing is usually performed using a slurry which often contains a mixture of minerals, sludge or other suitable materials dispersed in liquid. For example, the slurry contains colloidal silica which is a compound of amorphous anhydrous silicic acid in a colloidal state, and abrasive particles used for chemical-mechanical planarization/polishing (CMP).